Twist-drill.



J. B ooooo B. Twls TTTTT L.

APPLICATION FILED DBCLVI B 1 9 1 3.

lINITED STATES PATENT @FFIQE JOHN B. MOORE, OF LATROBE, PENNSYLVANIA,ASSIGNOR TO LATROBE TOOL COMIPANY, OF LATROBE, PENNSYLVANIA, ACORIPORATION OF PENNSYLVANIA.

TmsT-JJR-ILL.

Application filed December 18, 1913.

To ali whom it may concern:

Be it known that I, JoHN B. MooRE, a citizen of the United States,residing at Latrobe, in the county of Westmoreland and State ofPennsylvania, have invented new and useful Improvements in Twist-Drills, of which the following is a specifieation.

This invention relates `to an improvement in twist drills. I

Owing to the excessive cost of the high speed steels of which twistdrills, and the like, are usually constructed, attempts have been madefrom time to time to construct such drills in two parts by forming thebody or working portion of high grade material and securing the same toa shank of ordinary carbon steel. Such structures, however, are open tothe objection that they are weakest at lthe point of union between thebody and the shank, and arel easily broken at that point under thestrains encountered by the tool in operation.

One of the objects of the present invention is to produce a two partdrill, z'. e. a drill formed with a body of high speed steel and a shankof carbon steel, which will conform to the general outline of the oldstyle of drills constructed by milling, and which will have its greateststrength at the point of union between the body and the shank.

The invention will be hereinafter fully set forth and particularlypointed out in the claims.

In the accompanying drawing Figure 1 is a side view illustrating theblank of high speed steel from which the body of the tool isconstructed. Fig. 1*I is a sectional view. Fig. 2 is a similar view of ashank of lower grade material. Fig. 3 is a side view illustrating thefirst step of uniting the body and the shank. Fig. 4 is a viewillustrating the body and shank united ready for finishing. Fig. 5 is asectional view thereof and Fig. 6 is a view of the finished drill. Fig.7 is a view of a finished drill with a straight flute.

Referring to the drawings, 10 designates a blank of any suitable highgrade material of which the body of the drill is to be made, the samebeing provided with longitudinal grooves so as to be approximatelyX-shaped in cross section as indicated at 11. The shank member 12 oflower grade material Specification of Letters Patent.

Patented Deo. 20, 1914.

Serial No. 807,525.

is provided with a tang portion adapted to fit a drill socket, and it isalso provided with a portion 12a provided with recesses 13 so as tocause the same to conform to the cross section of the blank 10. Inpractice the blank 10 and the shank-member 12 are placed in a suitableelectrical welding apparatus, and united by a butt weld as indicated inFig. 3, the pressure of bringing the parts together causing the metal toSqueeze out at the joint to form what is termed the flash as indicatedat 111. This flash may be removed by any suitable means, if desired,although I do not find it necessary to the success of my invention, toso remove it. After the parts are welded together in the manner thusdescribed, I splice the joint formed by the welding, by filling in thegrooves 11 and recesses 13 with molten metal, preferably using theoxyacetylene blow pipe for the purpose of welding the splicing materialdirectly to the body and shank so as to become practically integraltherewith, as indicated at 15, Fig. 4:, Any suitable material may beused as a filling to form a. splice, and I do not desire to limit myselfin this particular. Excellent results have been obtained by using steel,phosphorbronze and the like. After the filling or splce has been appliedto the parts the tool is'ready for the final finishing steps, and afterthe body has been twisted and the drill finished the same presents theappearance illustrated in Fig. 6. Another form is illustrated in Fig. 7.In this connection it will be noted that the body of the drill is nottwisted, until after the same has been united to the shank. It will alsobe noted that while I have described my improved process in connectionwith twist drills I do not desire to limit myself in this particular asit is equally applicable to drills that are not twisted. It will befurther understood that while I have described the drill body as made offlat metal and twisted after its union to the shank member, I do notdesire to limit myself thereto, as it is obvious that the drill body maybe twisted. before the welding operation takes place.

From what has been said it will be observed that I have produced atwo-part drill comprising a body of high speed steel and a shank ofCarbon steel, which conforms in general Outline to the old style drillsmade by milling. It Will be further noted that the drill thusconstructed has no enlargements at the point of union between the bodyand the shank, and by reason of the splicing of the joint in the mannerdeseribed, the drill possesses greater strength at the joint thanelsewhere so that it Will not break at that point. Furthermore byuniting the body and the shank in the manner desoribed, the body may beheated and twisted Without in any manner impairing the joint with theshank.

Having thus explained the nature of my invention, and described anoperative manner of eonstructng and using the same, al-

though Without attempting to set forth all of the forms in which it maybe made, or all of the modes of its use, what I claim is 1. Animprovement in twist drills and the like comprising a body of high speedmetal and a shank of lo'\v grade metal having abutting ends weldedtogether, and a metal splice extending across the point of union andinseparably eonneeted With both the shank and the body.

2. An iniprovement in tWist drills and the like comprising a body ofhigh speed metal and a shank of low grade metal having abutting endsWelded together and provided With depressions, the depressions in unitedat their eontiguous ends, and a metalv' lic filling located in saidgroove and recess and extending longitudinally of the shank and body andacross the point of union of said body and shank.

4. An improvement in tWist drills and the like comprising a body ofapproximately X-shape in cross-section, a shank provided With a portioncorresponding to said body in cross-section, said shank and body havingabutting ends Welded together, \vhereby longitudinal grooves are formed,and inv tegral metallic splices extending across the point of union tosaid shank and vbody Within said grooves.

In testimony Whereof I have hereunto set my hand in presence of tWosubscrihing Witnesses. i

JOHN B. MOORE.

Witnesses:

J os. E. BARNnTT, F. B. MCFEELY.

Copies .of this patent may be obtained for five cents each, by aressngthe Gommissoner of Patent s,

Washington, D. 0. v i

